Over fire air jet for stokers



June 2 1950 w. M. $HWEICKART OVER FIRE AIR JET FOR STOKERS Filed July31, 1944 Ill I I I /N[/EN7'UR wnu/m. m. SCHWEICKART TTU A/E/ PatentedJune 20, 1950 William'ltf'. Schweickart, Bay Village, dhio as- I signerto Iron' Fireman Manufacturing Company, Portland; Oreg.

* Thisinvehtion relates H pammanyw a means for supplying overfire newthe combustion chamber in a furnace'. The main object of this inventionis toprovide a means-ionsupplying over fireair in order to burn as muchof the coke as possible from" the surface, leaving a lowertemperaturewithin the fuel bed, and thus reducing the tendency to form lifikrs onthegrates; p I" A "*Th'sec'o'rfd object is to make it possible to lowerthe air velcity through the tuyeres, thus-reducing the amount of fly ashproduced.

The third object is to reduce the amount of smoke formed by forcingsuflicient preheated air to impinge upon the forming coke as it emergesfrom the retort.

The fourth object is to provide an over-fire air jet which can besubstituted for one of the regular tuyere sections and in which it ispossible to use as many of the jets as desired and dispose them aroundthe periphery of the retort to suit any specific requirement.

The fifth object is to so construct the jet that the riser portionthereof may be disposed at any desired radius from the retort center andthat the horizontal connection between the tuyere section and the riseris protected by refractory material and ashes and whatever heat istransmitted thereto is absorbed by the air delivered to the jet andfinally reaches the combustion.

I accomplish these and other objects in a manner set forth in thefollowing specification as illustrated in the accompanying drawing, inwhich Fig. 1 is a fragmentary plan showing a retort and a plurality ofair jets in conjunction therewith.

Fig. 2 is a fragmentary section taken along the line 2-2 in Fig. 1.

Fig. 3 is a fragmentary end elevation taken along the line 33 in Fig. 2.

Fig. 4 is a transverse section taken along the line 4-4 in Fig. 2.

Fig. 5 is a transverse section taken along the line 5-5 in Fig. 2.

Similar numerals refer to similar parts throughout the several views.

Referring in detail to the drawing, there is shown the upper end ll] ofa retort, above which is disposed a locking ring II for the tuyereelements l2 which are made separate for manufacturing reasons, and forexpansion purposes. The tuyeres l2 have the usual inturned air ports l3which ports are downwardly inclined, and are held in position by meansof the ring H, which gen'el' allyto stol'iers and V v "litpicatit'iriiuly 31, 1944; serial No. 547,490

" 1 Claim. (01.1'10'475) e ages the notch:- l 4' formed in "eachelement'i I 2.

Such tuyere elements are now incommorr us'e, and supply air from theplenumchamber 15' to the tuyere elements l2; from whence E it escapes'through: the parts It toward the center "of the firebed. a

Referring particularly to" myinventiomlsa m'e will-be seen toconsistiof' a modi'fied form of tuyre section H5 which differs from theelements'fl in that it has an outwardly tu-rned fiar'igei [1, from whichradiates the horizontal connecting pipe l 8, which extends into theflange 19 formed on the lower elbow 20 of the vertical riser 2|,preferably of somewhat flattened cross section as shown in Fig. 4. Atthe upper end of the riser 2| is formed the elbow 22, having theinturned and somewhat depressed tip 23. The tip 23 is preferably roundas shown in Fig. 3, although it may assume any other desired shape. Itis desirable to cover the horizontal pipe l8 with a, refractory material24, to protect same. It is desirable to unite the parts 11 and 18 toclamp them in their proper relationship.

In some instances it may be found desirable to draw the air supply forthe riser 2| directly from the plenum chamber or from the fan itself,although the first described form of the device possesses the highlydesirable quality of being insertable into any sectional tuyere andselectively positioned about the periphery thereof, and moreover, iseasily replaced or changed should such action be found desirable.

It can be seen from the foregoing that any coke which forms in the fuelbed is burned as:

completely as possible from the surface by means of the air jets 25coming from the tips 23, thereby maintaining a lower temperature withinthe fuel bed and holding the ashes below the fusing point, and therebyreducing the tendency to form clinkers on the grates. It will also beseen that the presence of the over-fire jets 25 makes it possible tomaintain a lower air velocity at the tuyre ports l3, thereby reducingthe fly ash, which is highly desirable.

It will also be seen that by forcing preheated air against the formingcoke column, the combustion is improved and the amount of smoke formedis greatly reduced.

In practice, it is found that the quantity of air passing from the tips23 is normally held at approximately 40% to 50% of the total air supply.The velocity of the air leaving the tips 23 should be between 2,000 and3,000 feet per minute.

The apparatus above illustrated and described would be the type employedin clinker type equip- 3 ment, whereas when used in connection with ashremoval equipment, the passageway for the overfire air will be ledupward at an angle from the top of the tuyere blocks until a, diameterequal to that of the grate is reached. At that point it will passvertically to the desired height where it is turned downward forimpingement against the coke column."

I am aware that numerous attempts have been made to supply over-fire airto stokers. I therefore do not intend to cover such devices broadly butI do intend to cover all such-forms and modifications thereof as fallfairly within the appended claim. 4

I claim:

In an underfeed stoker, the combination of a retort having means forfeeding, coal thereto, means defining a. plenum chamber surrounding saidretort, tuyre blocks disposed around said retort, having downwardly andinwardly directed air passages therethrough which passages at theirouter end communicate with the plenum vchamber and at their inner endswith the interior of the retort, a horizontal pipe communicating withsaid horizontal pipe having a downwardly inclined tip at its upper end,pointed to- .ward the vertical axis of said retort and adapted 4 todischarge air toward a central coke column. above the top of theuppermost tuyre portion for the purpose of breaking up any coke columnwhich may be formed therein, said riser pipe extending upwardly abovethe uppermost portion of the tuyre blocks.

' WILLIAM M. SCHWEICKART.

REFERENCES CITED The following references are of record in th file ofthis patent:

UNITED STATES PATENTS Number Name Date 285,397 Dodge Sept. 25, 1883558,894 Boynton Apr. 21, 1896 624,009 Glessner May 2, 1899 839,003 KlineDec. 18, 1906 852,209 Watson Apr. 30, 1907 860,504 Treibel July,16,870,686 Reid Nov. 12, 1907 1,066,042 Parsons- July 1, 1913 1,138,060Gaines May 4, 1915 1,229,387 Willett June 12, 1917 1,387,453 Cole Aug.16, 1921 1,468,536 Lawter Sept. 18,1923 1,603,601 Hejma Oct. 19, 19261,607,312 Schierenbeck Nov. 16, 1926 2,068,018 Goetz Jan. 19, 19372.362.127

Gehl Nov.- 7. 1944

